• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.45-51
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• 2011

This paper proposes a method to accelerate the evolution speed of individuals through hybrid reproduction of monogenesis and gamogenesis. Monogenesis as a reproduction method that bacteria or monad without sexual distinction divide into two individuals has an advantage for local search and gamogenesis as a reproduction method that individuals with sexual distinction mate and breed the offsprings has an advantages for keeping the diversity of individuals. These properties can be properly used for improvement of evolution speed of individuals in genetic algorithms. In this paper, we made relatively good individuals among selected parents to do monogenesis for local search and forced relatively bad individuals among selected parents to do gamogenesis for global search by increasing the diversity of chromosomes. The mutation probability for monogenesis was set to a lower value than that of original genetic algorithm for local search and the mutation probability for gamogenesis was set to a higher value than that of original genetic algorithm for global search. Experimental results with four function optimization problems showed that the performances of three functions were very good, but the performances of fourth function with distributed global optima were not good. This was because distributed global optima prevented individuals from steady evolution.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.1
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• pp.52-64
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• 1995

Robot manipulator is a highly nonlinear-time varying system. Therefore, a lot of control theory has been applied to the system. Robot manipulator has two types of control; one is path planning, another is path tracking. In this paper, we select the path tracking, and for this purpose, propose the intelligent control¬ler which is combined with fuzzy logic and neural network. The fuzzy logic provides an inference morphorlogy that enables approximate human reasoning to apply to knowledge-based systems, and also provides a mathematical strength to capture the uncertainties associated with human cognitive processes like thinking and reasoning. Based on this fuzzy logic, the fuzzy logic controller(FLC) provides a means of converhng a linguistic control strategy based on expert knowledge into automahc control strategy. But the construction of rule-base for a nonlinear hme-varying system such as robot, becomes much more com¬plicated because of model uncertainty and parameter variations. To cope with these problems, a auto-tuning method of the fuzzy rule-base is required. In this paper, the GA-based Fuzzy-Neural control system combining Fuzzy-Neural control theory with the genetic algorithm(GA), that is known to be very effective in the optimization problem, will be proposed. The effectiveness of the proposed control system will be demonstrated by computer simulations using a two degree of freedom robot manipulator.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1120-1131
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• 2006

This paper describes the numerical analysis techniques using the Combined Integration/Matrix Method to calculate ground potential rise which can be occurred in the various grounding systems. Combined Integration/Matrix Method is used to reduce the error and computation time with the analytical integration equation and the proper segmentaion of earth embedded conductor. To do it, optimal segmentaion method for the buried conductors is presented through error analysis which is capable of applying the practical scaled various grounding systems. The optimum length of segmented element is much co-related with the buried depth of grounding electrode and the maximum length of buried electrode. As a result, less 3 precent errors was obtained by proposed model. The proposed model is applied to verify an effect of multi-grounding problems which was aroused much controversy with separated or common grounding between the high power grounding system and low power grounding system such as signal and telecommunication grounding.

• Journal of Embryo Transfer
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• v.28 no.4
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• pp.373-379
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• 2013

Spermatogonial stem cells (SSCs) developed into sperms through spermatogenesis have been utilized as a useful tool in the field of regenerative medicine and infertility. However, a small number of highly qualified SSCs are resided in the seminiferous tubule of testis, resulted in developing effective in-vitro culture system of SSCs for solving simultaneously quantitative and qualitative problems. Presently, SSCs can be enriched on testicular stromal cells (TSCs), but there are no systematic researches about TSC culture. Therefore, we tried to optimize culture condition of TSCs derived from mouse with different strains. For these, proliferation and viability were measured and compared by culturing ICR outbred or DBA/2 inbred mouse-derived TSCs at 35 or $37^{\circ}C$. In case of ICR strain, primary TSCs cultured at $37^{\circ}C$ showed significantly higher proliferation and viability than those at $35^{\circ}C$ and significant increase of proliferation and viability in sub-passaged TSCs was detected in the $35^{\circ}C$ culture condition. Moreover, sub-passage of primary TSCs at $35^{\circ}C$ induced no significant effects on proliferation and viability. In contrast, in case of DBA/2 strain, significantly improved proliferation were detected in the primary TSCs cultured at $35^{\circ}C$, which showed no significant difference in the viability, compared to those at $37^{\circ}C$. Furthermore, sub-passaged TSCs cultured at $37^{\circ}C$ showed no significant differences in proliferation and viability, compared to those at $35^{\circ}C$. However, with significant decrease of proliferation induced by sub-passage of primary TSCs at $35^{\circ}C$, no significant effects on proliferation and viability were resulted from sub-passage of primary TSCs at $37^{\circ}C$. From these results, culture temperature of primary TSCs derived from outbred and inbred strain of mouse could be separately optimized in primary culture and subculture.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.97-104
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• 2015

This study is a part of the high pressure injection system development on the Turbo GDI engine in order to reduce smoke emission in case of using the low volatile(high DI) fuel which is used as normal gasoline fuel in the US market. Firstly, theoretical approach was done regarding gasoline fuel property, performance, definition of particle matters and its creation as well as problems of the high DI fuel. In this experimental study, 2L Turbo GDI engine was selected and optimized system parameter was inspected by changing fuel, fuel injection mode (single/multiple), fuel pressure, distance between injector tip and combustion chamber, start of injection, intake valve timing in engine dyno at all engine speed range with full load. In case of normal gasoline fuel, opacity was contained within 2% in all conditions. On the other hands, in case of low volatile fuel (high DI fuel), it was confirmed that the opacity was rapidly increased above 5,000 rpm at 14.5 ~ 20 MPa of fuel pressure and there were almost no differences on the opacity(smoke) between 17 MPa and 20 MPa fuel pressure. According to the SOI retard, smoke decrease tendency was observed but intake valve close timing change has almost no impact on the smoke level in this area. Consequently, smoke decrease was observed and 16% at 6000rpm respectively with injector washer ring installed. By removing injector washer to make injector tip closer to the combustion chamber, smoke decrease was observed by 46% at 5,500 rpm, 42% at 6,000 rpm. It is assumed that the fuel injection interaction with cylinder head, piston head, intake and exhaust valve is reduced so that impingement is reduced in local area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.679-685
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• 2004

Although the electrophoretic deposition method has the advantage of simple processing procedure, less fabrication facilities, and easier control for deposition thickness and wire length, providing economical and technical merits, it also has the disadvantages of cracking and porosity phenomena, requiring an improved processing method for higher particle density and constant particle orientation. we have developed an optimization method to increase the particle density and to unify its orientation, and have performed a study to overcome the cracking and porosity problems in the fabricated superconductor. In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternate voltage vertically has been developed for the first time and applied to the electrophoretic deposition process. The applied alternate electric field caused a force to be exerted on each YBCO particle and resulted in a rotation of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. We name this process as the shaky-aligned electrophoretic deposition method. For commercial utilization and efficiency, in this dissertation, alternating voltage of 60 Hz and 25 ∼ 120 V/cm was proposed to apply it as a subsidiary source for shaky-flow deposition so that the fabricated thin film showed uniform surface morphology with less voids and cracks and Tc,zero of 90 K and the critical current density of 3419 A/$cm^2$.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.80-90
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• 2002

Clustering is a useful technique for grouping data points such that points within a single group/cluster have similar characteristics. Many clustering algorithms have been developed and used in engineering applications including pattern recognition and image processing etc. Recently, it has drawn increasing attention as one of important techniques in data mining. However, clustering algorithms such as K-means and Fuzzy C-means suffer from difficulties. Those are the needs to determine the number of clusters apriori and the clustering results depending on the initial set of clusters which fails to gain desirable results. In this paper, we propose a new clustering algorithm, which solves mentioned problems. In our method we use evolutionary algorithm to solve the local optima problem that clustering converges to an undesirable state starting with an inappropriate set of clusters. We also adopt a new measure that represents how well data are clustered. The measure is determined in terms of both intra-cluster dispersion and inter-cluster separability. Using the measure, in our method the number of clusters is automatically determined as the result of optimization process. And also, we combine heuristic that is problem-specific knowledge with a evolutionary algorithm to speed evolutionary algorithm search. We have experimented our algorithm with several sets of multi-dimensional data and it has been shown that one algorithm outperforms the existing algorithms.

• Journal of Korea Water Resources Association
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• v.50 no.3
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• pp.191-200
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• 2017

A robust parameter set (ROPS) selection framework for an unsteady flow model was developed by combining Pareto optimums obtained by outcomes of model calibration using multi-site observations with the minimax regret approach (MRA). The multi-site calibration problem which is a multi-objective problem was solved by using an aggregation approach which aggregates the weighted criteria related to different sites into one measure, and then performs a large number of individual optimization runs with different weight combinations to obtain Pareto solutions. Roughness parameter structure which can describe the variation of Manning's n with discharges and sub-reaches was proposed and the related coefficients were optimized as model parameters. By applying the MRA which is a decision criterion, the Pareto solutions were ranked based on the obtained regrets related to each Pareto solution, and the top-rated one due to the lowest aggregated regrets of both calibration and validation was determined as the only ROPS. It was found that the determination of variable roughness and the corresponding standardized RMSEs at the two gauging stations varies considerably depending on the combinations of weights on the two sites. This method can provide the robust parameter set for the multi-site calibration problems in hydrologic and hydraulic models.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.297-304
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• 2004

In this paper, a mesh simplification algorithm based on wavelet transform and 2D planar sampling is proposed for efficient handling of 3D objects in computer applications. Since 3D vertices are directly transformed with wavelets in conventional mesh compression and simplification algorithms, it is difficult to solve tiling optimization problems which reconnect vertices into faces in the synthesis stage highly demanding vertex connectivities. However, a 3D mesh is sampled onto 2D planes and 2D polygons on the planes are independently simplified in the proposed algorithm. Accordingly, the transform of 2D polygons is very tractable and their connection information Is replaced with a sequence of vertices. The vertex sequence of the 2D polygons on each plane is analyzed with wavelets and the transformed data are simplified by removing small wavelet coefficients which are not dominant in the subjective quality of its shape. Therefore, the proposed algorithm is able to change the mesh level-of-detail simply by controlling the distance of 2D sampling planes and the selective removal of wavelet coefficients. Experimental results show that the proposed algorithm is a simple and efficient simplification technique with less external distortion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.469-486
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• 2017

Economy-based urban redevelopment is the main priority in Malaysia, but has resulted in social problems such as gentrification, loss of heritage and identity, inequity, etc. Hence, it is crucial for the government to seek other alternatives rather than being solely reliant on urban redevelopment. Neighborhood renewal is a strategy involving the integration of redevelopment, rehabilitation, revitalization and preservation that aims to improve deprived areas using a more holistic approach. The aim of this paper is to review the neighborhood renewal policies in developed countries and to identify those elements that can be adopted in Malaysia. This study is conducted via a literature review. It was found that neighborhood renewal which integrates people-based, place-based and system-based policies highlights the importance of diversity, thereby aiming for resource optimization, community engagement and urban governance with the focal point of the fair, equity and systematic provision of resources. This paper concluded that neighborhood renewal in Malaysia should be initiated by locals with an emphasis on real local participation and a sustainable funding system. The government and local authorities should be observers rather than implementers.